CHEM 121 Final Exam

CHEM 121 Foundations of General Chemistry

Identify the following as one of the three domains of chemistry: a diamond ring

macroscopic

Identify the following as one of the three domains of chemistry: a white blood cell

microscopic

Identify the following as one of the three domains of chemistry: Pb(s)

symbolic

True or False: The 3 basic parts of a measurement are a number, a unit, and indication of the uncertainty of the measurement.

True

What is the mass of an iron cylinder, written with correct significant figures, that has a volume of 72.1 cm3 and a density of 7.87 g/cm3?

567 g

A puppy has a mass of 78.2 grams. This is an example of an —.

uncertain measurement

Three different volumes of water (20.57 mL, 9.3994 mL, and 11.286 mL) were added together in a beaker. How should the sum of these volumes be properly reported?

41.26 mL

What is the mass in grams of a baby who weighs 9.32 lb?

Use the following relationship, 1 lb = 453.59 g, and correct significant figures.

4,230 g

Which type of matter has a fixed shape and volume?

solid

Matter: chlorinated pool water

Type:

homogeneous mixture

Matter: carbon

Type:

element

Matter: chocolate chip cookie

Type:

heterogenous mixture

The density of copper is 8.93 g/cm?.This is a

physical property

Gasoline is highly flammable. This is a

chemical property

A car has a mass of 1,302 kg. This is a

physical property

When butter melts, this is a

physical change

When a car fender rusts, this is a

chemical change

When you bake a cake, this is a

chemical change

Which of the following is NOT an example of an extensive property?

The temperature of the water is 60°C.

Which of the following was J.. Thomson's biggest discovery in regards to subatomic particles?

He discovered the electron.

Which of the following was used by J.J. Thomson in his subatomic particle discovery?

cathode ray tube

The following symbols represent examples of

³⁵₁₇Cl ³⁷₁₇Cl

isotopes

Which of the following is the correct chemical symbol for an element that has 33 protons, 42 neutrons, 36 electrons?

⁷⁵₃₃AS^3-

Property Measured: length

Name of Unit: meter

Symbol of Unit:

m

Property Measured: mass

Name of Unit:

Symbol of Unit: kg

kilogram

Property Measured:

Name of Unit: cubic meter

Symbol of Unit: m³

volume

Property Measured: density

Name of Unit: kilogram per cubic meter

Symbol of Unit:

kg/m³

Property Measured:

Name of Unit: second

Symbol of Unit: s

time

Property Measured: temperature

Name of Unit:

Symbol of Unit: K

kelvin

Support or refute the following statement:

The amount of matter involved in a chemical or physical change remains constant.

Support or refute:

Explanation (at least 1 complete sentence):

support.

definition of the law of conservation of matter.

Give an example of a compound and explain your reasoning. Your answer should be at least 2 complete sentences and must be different from an example found on this exam.

An example of a compound is carbon monoxide.

One carbon atom and one oxygen atom come together to make carbon monoxide. pure substances that are comprised of two or more elements.

Define the term atom and give an example.

Definition (must be in a complete sentence):

Example:

smallest part of an element.

a single element He (helium).

Subatomic Particle in a Typical Atom: proton

General Charge:

positive

Subatomic Particle in a Typical Atom:

General Charge: negative

electron

Subatomic Particle in a Typical Atom: neutron

General Charge:

no charge

You are performing an experiment in the lab and have two different metal cylinders on your bench, each made of a different metal. You forgot to label which was which and they both look exactly the same. You do not have any extras so you cannot start over.

Based on what you have learned in this module, write out what steps you can take to quantitatively identify which is which. Your answer should contain at least 3 complete sentences to receive full credit.

determine volumes using water displacement or geometric measurement.

determine masses.

calculate densities.

compare densities to known values.

What is the volume of a sample of ethylene glycol if it has a density of 0.810 g/mL and weighs 36.9 grams?

Equation:

Equation with known values substituted:

Answer (with correct units and significant figures):

A short metal rod was submerged in a graduated cylinder partially filled with water. The initial volume of water in the graduated cylinder before the rod was added was 15.3 mL. After the metal rod was submerged, the volume in the graduated cylinder was 26.8 mL. The mass of the rod is 90.505 grams.

A. What is the density of the metal rod?

Equation:

Equation with known values substituted:

Answer (with correct units and to 3 significant figures):

B. Given the following information, what is the metal rod made out of?

Use dimensional analysis and the conversion factors below to perform the following unit conversion.

You must show the setup of the calculation and the final answer to receive full credit. You do NOT need to show your intermediate work.

A gasoline tank holds 15.0 gallons of gasoline. How many milliliters (mL) does the tank hold?

Setup:

Answer (with correct units and to 3 significant figures):

Use the following conversion factors to convert between the different temperature scales below.

232 K = —°F

Equations and calculations with values substituted:

Answer (with correct units and to 3 significant figures):

A sample of argon is found to contain 0.34% of 36 Ar atoms (mass 35.968 amu), 0.063% of 38 Ar atoms (mass 37.963 amu), and 99.60% of 40 Ar atoms (mass 39.962 amu. Calculate the average mass of an Ar

atom.

Setup:

Answer (with correct units and to 4 significant figures):